Master of Science (MS)
Physical activity may increase long bone calcium (Ca) content to preserve bone strength in postmenopausal women. This study determined the effect of compulsory swimming and voluntary running exercise on bone mineral density, bone Ca and phosphorus (P) content, and femoral neck and tibia strength in ovariectomized (OVX) retired breeder rats, as a model for postmenopausal women. Thirty-seven nine-month old Sprague Dawley rats were assigned randomly into one of four treatment groups for the nine-week study: OVX + running (OR; n=9); OVX + swimming (OS; n=10); OVX + no exercise (O; n=9); sham-surgery + no exercise (Sh; n=9). OR rats had free access to running wheels; OS rats were trained over one week to swim for one hour, five days a week. At sacrifice, femurs, tibias, humeri, and vertebrae were removed. Bone mineral density was analyzed using pDEXA, and bone Ca and P content were analyzed using atomic absorption spectrometry and colormetric assay, respectively. Femur and tibia strength was determined by Q-tester. Bone mineral density was significantly higher for all bones measured in the exercise groups compared to the sedentary groups. Mean grams (g) of Ca per dry femur weight for OS rats were higher than O rats (p=0.019). Tibias of the OR and OS rats were able to absorb significantly more energy to break load than the O rats (p=0.000; p=0.001, respectively), and energy absorption was significantly higher for the OR compared to Sh tibia (p=0.022). No other significant differences in parameters were observed among the four groups. Results of this study suggest that both types of exercise improve bone mineral density, that swim exercise may be beneficial in preserving femur Ca content, and that swim exercise and voluntary running may be beneficial in improving tibia strength in OVX rats.
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Duhe, Shelly Ann, "Swimming versus voluntary running exercise on bone health in ovariectomized retired breeder rats" (2003). LSU Master's Theses. 1813.